The first International Underground Film Festival is held at the NFT, organised by the Robert Street Arts Lab, the co-op, the Other Cinema and other independent film distributors, with the purpose of bringing together film-makers and films from the international scene. Deliberately unselective (but restricted by our inability to pay full travelling expenses to those with furthest to travel), the Festival was nonetheless important as an occasion on which European and American film-makers were able to show each other the kind of work they were producing.
David Curtis, 'English Avant-Garde Film, an Early Chronology', Studio International Nov/Dec 1975

The International Underground Film Festival represented the first British film festival dedicated solely to avant-garde filmmaking. Taking the Knokke Experimental Film Festival in Belgium as it's inspiration, the festival attested to the new level of organisation and interest in alternative film culture which had developed in Britain since the formation of the London Filmmakers' Co-op in 1966. Although there were as yet relatively few British filmmakers to be represented in the festival, the diverse range of filmmakers showing work from America and Europe indicated how far experimental filmmaking had developed in the post war period, with it's own networks of Co-operatives and screenings which now had an international momentum. The burgeoning filmmaking activity developing across Europe, and evident at the festival, was also beginning to challenge that of the American avant-garde, which had played a dominant role in alternative film culture until this point.

The festival ran from September 14th to 20th at the National Film Theatre, and was composed of presentations from the many film Co-operatives which had been established throughout Europe alongside screenings of the more established filmmakers from America, with well- known figures of the Underground film movement such as George Kuchar and Gregory Markopoulos presenting special screenings of new work. The festival showed the truly international reach of it's programming by beginning with films from the Sidney Film-makers Co-operative which was followed over the week by presentations from co-operative groups in Italy, Spain, Germany, Holland, Belgium and Germany. The broad range of interests and agendas of the festival organisers is also reflected in the programming, with the inclusion of more overtly political films from groups such as the French and Belgium political filmmaking collectives as well as a number of programmes by British filmmakers working on the small 8mm film format.

The festival title of 'International Underground' suggests that the organisers and filmmakers alike saw themselves as part of a wider movement in an alternative culture which also embraced happenings, experimental theatre and music events such as those at the UFO Club. The festival programming reflected this mixing of the arts and popular culture with the inclusion of a pop film programme and expanded cinema events by the Brighton based filmmaker Jeff Keen and the seminal performance artist Carolee Schneemann. The inclusion of the more austere and confrontational expanded films of the Austrian artists Valie Export and Peter Weibel, and those of Peter Kulbelka and Kurt Kren in particular was to make an impression on London filmmakers, foreshadowing the concern with formal or 'structure' film which to be a hallmark of British experimental filmmaking later in the decade. The British filmmakers included in the festival included; Malcolm le Grice, Fred Drummond, Mike Leggett, Graeme Ewens, whilst Steven Dwoskin, one of the London Filmmakers' Co-op co-founders, presented his new experimental feature, Times For.